SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eb557138b20c1af11958663ad8317b64c87ef2a08772765047b70ebae7e1dc1' 
  AND token = 'RN9jh7Df0o0EIvZ/fgmZyY1tuUSPXHtvED/nN3sKfmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}